The table below shows the number of foot bones in some horse fossils.

Horse Fossil Record

Horse Fossil Number of Foot Bones

P 19

Q 17

R 24

S 13

Ancient horses had more bones in their foot then present-day horses. The present-day horse has 11 foot bones. What is the correct order of evolution of the horse starting from the youngest fossil? A. Q P R S B. S R P Q C. S Q P R D. R P Q S

S Q P R

Explanation:

They said from the youngest bone to the oldest so do Least to greatest! Tell me if I am wrong

The correct answer is - D. R P Q S.

The fossil record of the horses show us that the horses started with bone structure in their legs as most four-legged mammals, by having 24 bones. As their environment was changing, they were adapting in accordance to it, so they started living in grasslands instead of forests, which meant more nutrition in their diet. That led to increase in their size, but since they also needed speed, they started to lose some of toes gradually, and developing less but much thicker and stronger bones in order to be able to run faster and still the leg to able to support their body weight. That constantly led to a decline in the number of bones in their legs, until they reached the present day form they have with 13 bones.